1. Field of the Invention
The present invention relates in general to a method and an apparatus for assembling a vehicle body, and more particularly to a method and an apparatus for assembling various types of vehicle bodies by using a flexible manufacturing system (FMS).
2. Description of the Prior Art
Hitherto, in order to assemble various types of vehicle bodies in a common assembling line, a so-called "flexible manufacturing system (FMS)" has been used. In the assembling line of this system, bypass lines are associated with a work supply line for selectively supplying certain works (e.g., main floor panels, body side panels, roof panels and the like) to the work supply line, and a plurality of locating robots and welding robots are associated with a vehicle body assembling device for locating and initially welding the works in accordance with information on the type of vehicle bodies which are to be assembled. Each time the type of the vehicle bodies to be assembled is changed, a so-called "mode change means" of the assembling device is actuated to change the positions at which the corresponding works are located by the robots. The locating robots of this type are disclosed in Japanese Patent First Provisional Publication No. 62-110581.
The robots employed in the above-mentioned assembling line are controlled by a series of control programs executed by a computer. Thus, if the series of programs has a part which is impossible to correctly execute, subsequent operation of the robots is inevitably suppressed. That is, hitherto, once the mode change means of the locating robots fails to operate due to trouble in the hardware and/or software, the entire body assembling line is compelled to stop until the trouble is settled. In fact, usage of numerous robots increases the possibility of inducing such troubles.